Fig. 5. MIS upregulates SMAD8, downregulates SMAD5 and induces Alk2 and Alk3 expression in urogenital ridges. Male or female urogenital ridges harvested at E14.5 were untreated or treated with MIS in organ culture for 20 hours (A-L), 12 hours (M-P) or 30 hours (Q-T). Transcripts of SMAD8 (A-F), SMAD5 (G-L), ALK2 (M-P) and ALK3 (Q-T) were detected by whole-mount in situ hybridization (A-C,G-I,M,N,Q,R), and their expressions are also shown after cryosectioning (D-F,J-L,O,P,S,T) at the broken lines. Arrows indicate the presence of expression. Cranial is oriented towards the top and Müllerian duct towards the right of individual whole-mount images. M, Müllerian duct; Ov, ovary; T, testis; W, Wolffian duct. Scale bar: 500 µm for all the whole-mount samples and 50 µm for all the cross-sections.